Aphonopelma chalcodes, commonly known as the western desert tarantula, Arizona blond tarantula or Mexican blond tarantula is a species of spider

Spider

Spiders are air-breathing arthropods that have eight legs, and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms...

 belonging to the family Theraphosidae. It has a limited distribution in the deserts of Arizona

Arizona

Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...

 and adjacent parts of Mexico

Mexico

The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

 but can be very common within this range. The common name "blond tarantula" refers to the carapace

Carapace

A carapace is a dorsal section of the exoskeleton or shell in a number of animal groups, including arthropods such as crustaceans and arachnids, as well as vertebrates such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron.-Crustaceans:In crustaceans, the...

, which is densely covered in pale hairs and contrasts strongly with the all-dark legs and abdomen. The female body length is up to 56 mm, males only reaching 44 mm. The male aracneds are worth c. $60, the females offspring are most likely to be 80% female. therefore females are worth at most $20-$30.

Description

This 3 to 4 inch (70 to 100 mm) large bodied, burrowing spider is commonly seen during the summer rainy season in southwestern deserts. The female is usually a uniform tan color. The male has black legs, a copper-colored cephalothorax and a reddish abdomen. Their burrows can be as large as 1 to 2 inches (25 to 50 mm) in diameter, with some strands of silk across the opening.

Distribution and Habitat

The Arizona blond tarantula is typically found in saguaro-dominated plant communities. There are many similar species throughout the desert southwest, but they are difficult to differentiate.

Ecology

Tarantulas are nocturnal predators that never venture far from their burrows unless it is mating season. In winter they plug their burrows with soil, rocks, and silk and survive in a relatively inactive state. During this time the animals live off stored fat reserves.

Tarantulas have an interesting defensive capability in addition to venom. Some of the hairs on the top of the abdomen are specialized for defense. These urticating hairs, as they are called, are tipped with backward pointing barbs. If a tarantula is threatened in any way, it brushes these hairs into the face, paw or other body part of its attacker. Once these hairs are embedded, they are irritating and very difficult to remove because of the barbs.

Life History

Male tarantulas mature when they are 10 to 12 years of age, at which time they leave their burrows in search of females. Upon finding the burrow of a mature female—she’s usually at least 10 years old—the male will announce himself by stroking the silk at the top of the burrow and tapping particular sequences that the female responds to. During mating, the male must reach under the female to insert his pedipalp into her gonopore to deposit sperm. He is particularly vulnerable to predation by the female when mating. The male’s first pair of legs has a “spur”located behind the knee which he uses to hold the female above him during copulation. After copulation the male makes a hasty retreat. The female lays her eggs in a burrow, sometimes staying with them. The young remain in the burrow until they disperse.

Each time a female tarantula molts, typically once a year, she also molts the lining of her epigynum (the female reproductive structure) where the sperm are stored, so she must mate again before she can produce fertile eggs. The many tarantulas seen on the roads in Arizona during the summer rains (July, August, September) are usually males searching for mates. The male tarantula does not survive long after his summer mating. Sometimes the female makes a meal of the male, or another predator kills him. Sometimes he dies of exposure to heat and cold. Even in captivity, out of harm’s way, males only survive a few months after mating.